The only map sketched by Lawrence of Arabia is expected to fetch up to £100,000 when it goes under the hammer in London next month.
The map, on faded yellow paper, shows northern Arabia and was sketched by the famous adventurer and military commander some time between 1918 and 1922 as he described his battle alongside Arab troops.
It records a 'pivotal moment' in the Arab Revolt against the Ottoman Empire that led to the capture of the Red Sea port town Aqaba in 1917.
Experts believe it is the only map depicting the journey Lawrence took across the hostile Saudi Arabian desert in 1917, which eventually led to the capture of a major port.
It shows the route he and a group of Arab armies followed after leaving the port of al Wejh, and then reaching the Hejaz railway.
A spokesman for Sotheby's, which is hosting the sale, said: 'On May 19th they embarked on the next stage of their trek into the barren lands towards Wadi Sirhan - the historic route that is recorded in this map.
'Lasting five days until the 24th May 1917, this journey would prove to be one of the most hazardous expeditions Lawrence ever undertook in Arabia.'
The drawing was done for a well-known cartographer and explorer called Douglas Carruthers who Lawrence befriended towards the end of the war.
Lawrence knew that his travels towards Aqaba were of interest to cartographers and carefully created the map for his friend by carefully plotting the route on a single sheet of paper, signing it and writing the words ‘This is the only drawn copy so please do not lose it prematurely’.
In 1962 it was donated to the Royal Society of Asian Affairs, where it has remained until now.
Experts noted that even a seasoned traveller like Lawrence, who inspired a 1962 Hollywood film starring Peter O'Toole, remarked upon the desert's harshness, writing on the side of the map: 'Air streaming past as thick smoke with dust sun-blinking in it. Iridescent dusk.'
He also wrote about the hot mudflats: 'Sun reflects from them like mirror - flame-yellow, cutting into our eyes like glare burning glass on closed lids. Head if veiled too hot: Besides camel might stray... Heat in waves and eyes often going black.'
The lot is listed for 4 November at Sotheby's Travel, Atlases, Maps and Natural History auction.
